<div class="left-menu">
    <div @click="isCollapse = !isCollapse" style=" background: #409EFF;padding: 8px 0"><i class="el-icon-menu" style="color:white;font-size:20px"></i></div>
    <el-menu default-active="1-1" class="el-menu-vertical-demo" @open="handleOpen" @close="handleClose" @select="selectItem"
        :collapse="isOpen" background-color="#283446" text-color="#fff" active-text-color="#ffd04b">
        <el-submenu index="1">
            <template slot="title">
                <i class="el-icon-location"></i>
                <span slot="title">导航一</span>
            </template>
            <el-menu-item-group>
                <span slot="title">分组一</span>
                <el-menu-item index="1-1">选项1</el-menu-item>
                <el-menu-item index="1-2">选项2</el-menu-item>
            </el-menu-item-group>
            <el-menu-item-group title="分组2">
                <el-menu-item index="1-3">
                    <template slot="title">
                        <i class="el-icon-location"></i>
                        <span slot="title">选项3</span>
                    </template>
                </el-menu-item>
            </el-menu-item-group>
            <el-submenu index="1-4">
                <span slot="title">选项4</span>
                <el-menu-item index="1-4-1">选项1</el-menu-item>
            </el-submenu>
        </el-submenu>
        <el-menu-item index="2">
            <i class="el-icon-menu"></i>
            <span slot="title">导航二</span>
        </el-menu-item>
        <el-menu-item index="3" disabled>
            <i class="el-icon-document"></i>
            <span slot="title">导航三</span>
        </el-menu-item>
        <el-menu-item index="4">
            <i class="el-icon-setting"></i>
            <span slot="title">导航四</span>
        </el-menu-item>
    </el-menu>
</div>